The colour of tomatoes is determined by the colour of the various compartments inside and outside the fruit. The three compartments are: the skin, the flesh and the seed pulp.
In red tomatoes the skin is yellow and the flesh is red. This gives the typical red hue of tomatoes. In pink tomatoes the skin is clear which lightens the red of the flesh to a pink
Yellow tomatoes come in two variants: yellow flesh with yellow skin and yellow flesh with clear skin. The clear skinned varieties give a paler fruit.
The situation with orange tomatoes is similar to that of yellow tomatoes. In both cases th flesh is orange, but the difference lies in the skin which can be clear and yellow. The brightest orange tomatoes have yellow skins, while the clear-skinned varieties are a pale orange.
Black tomatoes are quite special. To make the dark colouration the seed chamber usually has a dark green color. Combined with deep red flesh this can give two colour variants: brown and purple. The purple varieties have a clear skin while the brown varieties have a yellow skin.
There are two types of green tomaties. Both have green flesh but this can be combined with a clear or yellow skin.
True blue tomatoes are very special. They are unlike the other dark varieties. They collect a specific pigment in their skins that is also found in blueberries, anthocyanins. These molecules are known for their antioxidant properties, which promotes health.